The bizarre 11-10 final score was fitting because the Chargers still haven't had the regular-season finish they want in Pittsburgh: a winning one.

Ben Roethlisberger stayed away from the mistakes that cost the Steelers their previous two home games, Willie Parker ran for 115 yards and Jeff Reed's third field goal won it -- a 32-yarder with 11 seconds remaining -- as Pittsburgh rallied to beat the Chargers on a snowy Sunday.

The first such score in 12,837 NFL games was in jeopardy when Troy Polamalu returned an errant lateral 12 yards for an apparent touchdown on the final play. The play was overturned on review -- it was called an illegal forward pass -- and the 11-10 final was restored.

After the game, referee Scott Green said the officials realized afterward the touchdown should have counted, though it wouldn't have affected the result.

"It was weird," Steelers receiver Hines Ward said. "We definitely have to work on our offense. But this game is about wins and losses, and we won."

The only thing perfect on a snowy, frigid day when the weather and the offenses were equally awful was San Diego's regular-season record in Pittsburgh. Make it 0-13.

"I like playing on grass, mud, anything that slows down an offense," said linebacker James Harrison, who made a series of key plays.

Nate Kaeding put San Diego (4-6) up 10-8 with a 22-yard field goal with 6:41 to play, after missing from the 41 in the third quarter with the Steelers (7-3) leading 8-7.

Kaeding's miss came at Heinz Field's open end, where breezes blowing off the nearby three rivers cause tricky kicking conditions. Reed made his decisive kick at the same end following a 13-play, 73-yard drive in which Roethlisberger was 6-of-6 for 49 yards.

"I hit that one the best, and I knew it right away," Reed said.

The Steelers outgained the Chargers 410-213, and most teams with a 300-yard passer, a 115-yard rusher and a 124-yard receiver (Ward) normally have plenty of offense.

But the Steelers couldn't get into the end zone even as Roethlisberger went 31-of-41 for 308 yards against the NFL's worst passing defense, partly because they had 13 penalties for 115 yards to San Diego's two for 5 yards. Also, Mewelde Moore was stopped from a foot out on a fourth-and-goal play late in the first quarter.

A snow squall about 45 minutes before the late-afternoon kickoff coated Heinz's grass surface on a breezy, 35-degere day that began with a wind chill of 26. The mid-November conditions were a visible reminder of the warm-weather Chargers' struggles in Pittsburgh, where they have never won a regular-season game, although they are 2-0 there in the playoffs.

"I'm not going to say that snow didn't help us. It did," safety Ryan Clark said.

Roethlisberger wasn't intercepted after being picked off eight times, with only one touchdown pass, in his previous three games, including seven interceptions in successive home-field losses to the Colts (24-20) and Giants (21-14). Still, the Steelers' only scoring drives ended with Reed's field goals of 21, 41 and 32 .

"We've gotten into some close games and we haven't found a way to win. It was important for us to get into a close game like this and find a way to win," Aaron Smith said after Pittsburgh regained first place in the AFC North.

Reed's 21-yarder on the final play before halftime followed Harrison's interception of Philip Rivers' pass on a first-down play that began with the Chargers driving at the Steelers 17 -- a big swing in momentum. Rivers, the AFC's most efficient quarterback coming in, finished 15-of-26 for 159 yards and two interceptions even though Pittsburgh was missing two of its top three cornerbacks.

"Any time a defense gives up nine points, we should win the game," Rivers said. "We didn't get it done."

The Steelers' only other first-half scoring came when Harrison -- yes, him again -- sacked Rivers on a third-and-9 play from the San Diego 3, with the quarterback fumbling and left tackle Marcus McNeill recovering deep in his own end zone for a safety that made it 7-2.

The Chargers, coming off a 20-19 win over Kansas City that followed three losses in four games, led 7-0 after LaDainian Tomlinson scored on a 3-yard run midway through the first period, his first scoring run in 93 carries. He ended with 57 yards on 18 carries.

San Diego began that drive at its own 41 after Reed couldn't convert from 51 yards out on the slippery turf, his first miss in 20 attempts.

Game notes
Chargers DE Luis Castillo left in the third quarter with a groin injury and did not return. ... The Steelers have only three days off before playing Cincinnati, which tied the Eagles 13-13 -- the NFL's first tie in six years. ... San Diego is 0-3 in Eastern time zone games. ... Reed hadn't missed since a failed 44-yarder in ankle-deep mud during a last-minute, 3-0 win over Miami last Nov. 26.